Method for cleansing surfaces of buildings and passage-ways

ABSTRACT

A method for cleansing the exterior surface of a building of masonry, stone, brick or the like by which a jet of water at a temperature of not less than 100*C. is directed by a nozzle in close juxtaposition to such surface under a pressure of about 20 atm. so that the larger quantity of water does not vaporize before touching the surface to be cleaned. As a result, the water vaporizes either on or in the exterior coating of the surface being cleaned so that when expanding the steam presses the dirt etc. from the pores, capillaries and fissures of the surface. A solution is brushed or sprayed on the cleansed surface to render it water resistant.

United States Patent [191 Scheel et al.

[ METHOD FOR CLEANSING SURFACES OF BUILDINGS AND PASSAGE-WAYS [76]Inventors: Klaus Scheel, l'lerscheider Landstrasse 47, 588 Ludenscheid;

Wolfgang Luthe, Kunostrasse 8, 58 Hagen, both of Germany 22 Filed: Apr.23, 1973 21 Appl. No.: 353,367

[30] Foreign Application Priority Data Apr. 26, 1972 Sweden 5496/72 [52]US. Cl. 134/34; 134/35; 134/37 [51] Int. Cl. B08B 3/02 [58] Field ofSearch 134/34, 35, 37; 239/13 [5 6] References Cited UNITED STATESPATENTS 1,117,814 11/1914 Dutton 134/37 UX 1,925,643 9/1933 Ofeldt.....2,015,875 10/1935 Sloan 2,768,101 10/1956 Fairchild 134/34 [451 July 22,1975 3,196,888 7/1965 Rousseau 134/34 X 3,380,658 4/1968 Stasz et a1134/34 X 3,511,707 5/1970 Laflamme 134/27 [57] ABSTRACT A method forcleansing the exterior surface of a building of masonry, stone, brick orthe like by which a jet of water at a temperature of not less than 100C.is directed by a nozzle in close juxtaposition to such surface under apressure of about 20 atm. so that the larger quantity of water does notvaporize before touching the surface to be cleaned. As a result, thewater vaporizes either on or in the exterior coating of the surfacebeing cleaned so that when expanding the steam presses the dirt etc.from the pores, capillaries and fissures of the surface. A solution isbrushed or sprayed on the cleansed surface to render it water resistant.

1 Claim, No Drawings METHOD FOR CLEANSING SURFACES OF BUILDINGS ANDPASSAGE WAYS BACKGROUND OF THE INVENTION The invention deals with "atechnique as to how to treat surfaces of buildings and passage-ways, asalso bridgesand airport tarmacs. The invention is based on the use ofheated water, which is sprayed against the area which is to be cleansed.

In consequence of the increasing air pollution'by, among a number ofother things,'automobiles and industry, the probletn of pollution anddestruction of buildings has become a lot more obvious. The destructionis connected with the entrance of such aggressive exhaust components assulphur dioxide dissolved in water and turned to sulphuric acid which inpores and capillary tubes thus penetrate the'exterior areas. The resultis that the exterior areas decay. There are sufficient examples,especially on the European mainland, which clearly show and'prove thatirretrieveable and valuable buildings, sculptures and diverse culturalmonuments, have suffered extensive damage due to these attacks on thembyenvironmentally damaging materials. Mostly endangered are, of course,soft materials, such as sandstone, and limestone, which were the mostfrequently and'exten'sive'ly used for building materials inthe past. f

To preserve and maintaininvaluable and irreplaceable treasures ascultural monuments, on the one hand, and combat destructive effects tomodern buildings on the other hand; it has been appreciated afterrecognition of the necessity, that the surfaces of buildings andpassage-ways be treated by washing and impregnation to make theseinsensitive with regard to the all destructive effects of polluted air.

There are various cleansing methods available. The most usual being themethod utilizing water, steam or a chemically composed cleansingsolution. Hot water is used, among other purposes, to cleanseautomobiles, oil tanks, and many more severely dirtied surfaces of metalor similar material. One well known method involves the utilization ofchemical preparations in connection with water under high pressure.

After this, the dirt which has just been loosened with the aid of thischemical solution is washed off by the high pressure water spray. Forthis operation, a pipe is used where the nozzles are positioned atapproximately one meter or more above the dirty surface. Thedisadvantage of this cleansing method is that the chemicals which areapplied to the area to be cleansed through the subsequent high pressurewashing are forced into the pores of the material and stay there. Apartfrom this fact, high pressure washing as used damages the material.

After cleansing, the surface area is generally impregnated with apreparation, as for example, with silicic acid solution. However, as ithas not as yet been possible in the case of known and practiced methodsof cleansing to cleanse the pores and capillaries, the molecules of theimpregnation medium are not firmly anchored deeply enough with theexterior coat of the material, thus these are readily loosened again asfor example, when subjected to the power of rain downpours, hailstones,and the like.

SUMMARY OF THE INVENTION This invention relates to a method of depthcleansing of exterior surfaces of buildings and passage-ways of masonry,stone, brick,- and the like and which is based on the use of hot waterunder relatively high pressure. The heated water is forced with greatpower into the pores of the exterior surface. There it is vaporized. Inthe process, salt residue, chemicals, dirt collection, water residue,etc. are catapulted out. The surface thus treated has applied to it animpregnation solution once or several times, as required. As a result,the exterior surfaceacquires a water resistant quality which permits avapor diffusion out of thebuilding wall into the atmosphere.

DESCRIPTION OF THE PREFERRED EMBODIMENT The method in accordance withthe invention is thus mainly determined in. that the exterior surface iscleansed by water at a temperature of more than C forced under pressurethrough a nozzle which is held at an almost exact right angle againstthe area to be cleansed. The nozzle is guided translatorily parallel tothe surface to be cleansed. The nozzle should be no more than 2 cm fromthe area to be cleansed so that most of the water particles do notvaporize before the jet touches the surface, whereby the water either onor in thesurface coat finally vaporizes. This enables dirt and dirtycapillary water to be washed out when the expanding vapor presses out ofthe pores, capillaries and fissures of the exterior coat. Furthermore,this makes the impregnation of the deeply cleansed exterior coatpossible, as required.

In the case of severely dirty surfaces, the most severe dirt is removedby holding the nozzle tangential to the area. Thus, the dirt particlesare loosened by the power of the jet. After doing this, the surface areais cleansed as above set forth.

For the purpose of impregnation, various solutions may be used e.g.,solutions which are composed of certain mixtures containing alkyl,alkoxy, and silan. These solutions are dissolved in alcohol and thenapplied to the cleansed area, either by use of a brush or by spraying.Alternatively, the building materials are impregnated with this solutionafter first being cleansed. These solutions are usually based oncompositions which, under the influence of damp air become hydrolized,and, thus, form a direct binding to the binding mediums of the buildingmaterials. The groups of organic silicate acid compositions are directedto the surface area, and the water resistant effect is attained bycovering the area of the material evenly with a coating of a compositionof a hydrophobic organic group which increases the interior tensiontoward the water. This coating on the surface area increases theexterior tension towards water and thus reduces the suction capacity ofthe exterior area capillaries.

The method depends on the use of special aggregates, the pressure of thewater is produced by a pump and in which the water is heated to aminimum of 100C. An operating pressure of 20 atm. is best adapted at theentrance of the nozzle. When the heated water or steam passes thenozzle, the pressure drops rather quickly to atmospheric pressure,whereas the water temperature does not drop at the same rate. As aresult, the water is thus overheated at the entrance of the nozzle dueto this delay in boiling. vaporization begins'probably in the nozzleoutlet. The velocity of the jet is increased considerably. vaporizationis only combeen stated, is the bases upon which the impregnation fect,the water jet should be concentrated when it hits the surface areaqvltmust possess sufficient energy so that the vaporization may enter intothe exterior'coating. Should the distance be large, the jet loses itselfwith respect to concentration because too much water vaporizes duringthe boiling procedure while, at thesame time, the jet temperature falls.i Also the form of the nozzle is of significance towards attaining therequired technical effect. A certain minimum quantity of water per timeunit must be, released at the pressure andtemperature required foroperation to prevent all the waterfrom vaporizing when the jet leavesthe nozzle. v

Furthermore, there is an aspect noticeable in this in vention techniquewhich can contribute towards the attainment of the required effect. Whenthe well concentrated jet touches the surface area, a part of the jetpressure is retained in the pores as a result 'of the jet impulse, whichleadsv to areduction in vaporization and the steam bubble composition inthe jet is reduced also. When the nozzle is turned to the side thepressure is temporarily reduced. Thisleads to a speedy vaporization ofthe over-heated water and .contributes very much to the'attainment ofthe desired technical effect.

Based on measurements, it has been found that with the hot water at adischarge temperature of 130C. at the discharge end of the directingnozzle, the nozzle has to be held at'a maximum distance of twocentimeters from the surface being cleaned in order to achieve propervaporization of the water in the hollow capillary compartment's.

We claim:

1. Method of cleansing the exterior surface of a building of masonry,stone, brick or the like, comprismg I I a. directing a jet of water at atemperature not less than about 100C. from a nozzle at a pressureofabout 20 atmagainst the surfaceto be cleaned,

b. disposing said water jet at approximately right angles tosuch surfacewith the end of the nozzle spaced at a maximumldistance of about 2 cmfrom v the surface, and i c. moving the water jet parallel to suchsurface while maintaining same in said right angle position,

, whereby due to the proximity of the jet to such surfacethe greatervolume of water does not'vaporize before touching'thefsurface and partof the water is forced into the pores for achieving vaporizationtherein. I

1. METHOD OF CLEANING THE EXTERIOR SURFACE OF A BUILDING OF MASONRY,STONE, BRICK OR THE LIKE COMPRISING A. DIRECTING A JET OF WATER AT ATEMPERATURE NOT LESS THAN ABOUT 100*C. FROM A NOZZLE AT A PRESSURE OFABOUT 20 ATM AGAINST THE SURFACE TO BE CLEANED, B. DISPOSING SAID WATERJET AT APPROXIMATELY RIGHT ANGLES TO SUCH SURFACE WITH THE END OF THENOZZLE SPACED AT A MAXIMUM DISTANCE OF ABOUT 2 CM FROM THE SURFACE, ANDC. MOVING THE WATER JET PARALLEL TO SUCH SURFACE WHILE MAINTAINING SAMEIN SAID RIGHT ANGLE POSITION, WHEREBY DUE TO THE PROXIMITY OF THE JET TOSUCH SURFACE THE GREATER VOLUME OF WATER DOES NOT VAPORIZE BEFORETOUCHING THE SURFACE AND PART OF THE WATER IS FORCED INTO THE PORES FORACHIEVING VAPORIZATION THEREIN.